[PATCH 2/2] core: add core.convertAwareStatus to opt out of the content check

@@ -156,6 +156,28 @@ some fields (e.g. JGit); by excluding these fields from the
 comparison, the `minimal` mode may help interoperability when the
 same repository is used by these other systems at the same time.
 
+core.convertAwareStatus::
+	When a path is subject to content conversion -- the `text` and
+	`eol` attributes, `core.autocrlf`, a `working-tree-encoding`,
+	or a clean filter -- the size of the file in the working tree
+	is not determined by its contents alone, so a change in size
+	does not prove that the contents changed.  When this variable
+	is missing or set to `true`, Git reads and converts such a
+	file before reporting it as modified, which keeps 'git status'
+	in agreement with 'git diff' and 'git add'.  When set to
+	`no-filter`, Git does this only for the conversions it
+	performs itself, and a path with a clean filter configured
+	(Git LFS, for example) is reported as modified on a size
+	change without running the filter.  When set to `false`, a
+	size change is always taken as a modification, which is what
+	Git did before this variable existed.
++
+Reading the file costs more than trusting its size, so `no-filter`
+and `false` trade this consistency for speed in repositories where
+running the filter, or reading the file at all, is too expensive.
+Paths that are not subject to conversion are decided on the size
+alone in every mode.
+
 core.quotePath::
 	Commands that output paths (e.g. 'ls-files', 'diff'), will
 	quote "unusual" characters in the pathname by enclosing the

@@ -344,6 +344,19 @@ int git_default_core_config(const char *var, const char *value,
 				     var, value);
 	}
 
+	if (!strcmp(var, "core.convertawarestatus")) {
+		int b = git_parse_maybe_bool(value);
+		if (0 <= b)
+			cfg->convert_aware_status = b ? CONVERT_AWARE_STATUS_ALL
+						      : CONVERT_AWARE_STATUS_NEVER;
+		else if (value && !strcasecmp(value, "no-filter"))
+			cfg->convert_aware_status = CONVERT_AWARE_STATUS_IN_PROCESS;
+		else
+			return error(_("invalid value for '%s': '%s'"),
+				     var, value);
+		return 0;
+	}
+
 	if (!strcmp(var, "core.quotepath")) {
 		quote_path_fully = git_config_bool(var, value);
 		return 0;

@@ -766,6 +779,7 @@ void repo_config_values_init(struct repo_config_values *cfg)
 	cfg->apply_sparse_checkout = 0;
 	cfg->trust_ctime = 1;
 	cfg->check_stat = 1;
+	cfg->convert_aware_status = CONVERT_AWARE_STATUS_ALL;
 	cfg->zlib_compression_level = Z_BEST_SPEED;
 	cfg->pack_compression_level = Z_DEFAULT_COMPRESSION;
 	cfg->precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */

@@ -115,6 +115,12 @@ enum object_creation_mode {
 	OBJECT_CREATION_USES_RENAMES = 1
 };
 
+enum convert_aware_status {
+	CONVERT_AWARE_STATUS_NEVER = 0,
+	CONVERT_AWARE_STATUS_IN_PROCESS,
+	CONVERT_AWARE_STATUS_ALL
+};
+
 struct repo_config_values {
 	/* section "core" config values */
 	char *attributes_file;

@@ -130,6 +136,7 @@ struct repo_config_values {
 	int apply_sparse_checkout;
 	int trust_ctime;
 	int check_stat;
+	enum convert_aware_status convert_aware_status;
 	int zlib_compression_level;
 	int pack_compression_level;
 	int precomposed_unicode;

@@ -554,9 +554,21 @@ static int size_change_is_conclusive(struct index_state *istate,
 				     const struct cache_entry *ce,
 				     struct stat *st)
 {
+	struct repo_config_values *cfg = repo_config_values(the_repository);
+	struct conv_attrs ca;
+
+	if (cfg->convert_aware_status == CONVERT_AWARE_STATUS_NEVER)
+		return 1;
+
 	if (!S_ISREG(st->st_mode))
 		return 1;
 
+	if (cfg->convert_aware_status == CONVERT_AWARE_STATUS_IN_PROCESS) {
+		convert_attrs(istate, &ca, ce->name);
+		if (ca.drv)
+			return 1;
+	}
+
 	return !would_convert_to_git(istate, ce->name);
 }
 

@@ -442,4 +442,51 @@ test_expect_success 'status sizes a text file by its CRLF pairs, not its CRs' '
 	)
 '
 
+test_expect_success 'core.convertAwareStatus=false restores the size shortcut' '
+	git init convert-aware &&
+	(
+		cd convert-aware &&
+		echo "* text eol=lf" >.gitattributes &&
+		printf "one\ntwo\nthree\n" >file.txt &&
+		git add .gitattributes file.txt &&
+		git commit -m initial &&
+		printf "one\r\ntwo\r\nthree\r\n" >file.txt &&
+
+		git -c core.convertAwareStatus=false status --porcelain -uno >actual &&
+		echo " M file.txt" >expect &&
+		test_cmp expect actual &&
+
+		git -c core.convertAwareStatus=true status --porcelain -uno >actual &&
+		test_must_be_empty actual
+	)
+'
+
+test_expect_success 'core.convertAwareStatus=no-filter leaves clean filters alone' '
+	git init convert-aware-filter &&
+	(
+		cd convert-aware-filter &&
+		write_script stripcr <<-\EOF &&
+		tr -d "\015"
+		EOF
+		echo "file.txt filter=stripcr" >.gitattributes &&
+		git config filter.stripcr.clean ./stripcr &&
+		printf "one\ntwo\nthree\n" >file.txt &&
+		git add .gitattributes file.txt &&
+		git commit -m initial &&
+		printf "one\r\ntwo\r\nthree\r\n" >file.txt &&
+
+		git -c core.convertAwareStatus=no-filter status --porcelain -uno >actual &&
+		echo " M file.txt" >expect &&
+		test_cmp expect actual &&
+
+		git status --porcelain -uno >actual &&
+		test_must_be_empty actual
+	)
+'
+
+test_expect_success 'core.convertAwareStatus rejects an unknown value' '
+	test_must_fail git -c core.convertAwareStatus=bogus status 2>err &&
+	test_grep "invalid value" err
+'
+
 test_done